A little more than you want to speed, but I am super happy with the Nitto 555 Extreme http://www.discounttiredirect.com/direct/tires/nitto/size/viewProductDetail.do?pc=40139
:welcomenym::wave::wave::wave: The CS is a good looking package and the vert sends it over the top. I expect to see ya around when the sun is shinning!
This is a known problem on Cobras and Lightnings so it may also apply to other Fords. Some heads have 4/5 threads and others have 9. There are a bunch of threads on SVTPerformance on this issue such as this one...
They are bigger than that and usually go for around $600.00.
They also made one of the earlier non-supercharged Cobra Motor. Here is a few photos for ya